A mechanical or expanding-blade broadhead is a type of broadhead in which the blades are operably coupled to the ferrule in a manner to move from an in-flight, retracted position to an on-impact, deployed position. This configuration of a broadhead is beneficial in that it has flight characteristics similar to those of a field point tip and penetration characteristics similar to those of a fixed blade broadhead.
The most popular type of mechanical broadhead has one or more blades located within a slot such that the cutting edge is on the radially inward edge of the blade. The blade is pivotally coupled to the rearward portion of the ferrule so that it may rotate from a retracted position to a deployed position about the pivot on impact within a target, thereby exposing the cutting edge formed on the blade. This type of mechanical broadhead has performed with varying degrees of success. However, substantial kinetic energy is required to rotate the blade about the pivot from the retracted position to the deployed position. As a result, less kinetic energy is available for target penetration on impact.
Another less-common type of mechanical broadhead includes one or more blades which longitudinally slide relative to the ferrule from the in-flight, retracted position to the on-impact deployed position. Specifically, the blades in this sliding-type mechanical broadhead are disposed within a longitudinal groove formed in the ferrule such that the cutting edge of the blades extend radially outwardly. A lost-motion slot is formed in the interior of the blade and receives a pin extending through the ferrule to operably couple the blade thereto. During flight, the blades are closely positioned to the ferrule, and upon impact the blades slide rearwardly through a range of motion defined by the slot to the deployed position.
The sliding-type mechanical broadhead are in principle better than the pivoting-type mechanical broadheads in that they require less kinetic energy to move the blades from the retracted position to the deployed position. However, the current designs of such broadheads are less robust than other types of mechanical broadheads. Specifically, a ferrule in a sliding-type broadhead is typically fabricated from an aluminum alloy due to the required geometric complexity. Furthermore, the slot formed in the blades reduces the overall stiffness and durability thereof.
Recent developments in the broadhead art, and in particular use of powder injection molding for the manufacture of components, have added significant flexibility in the design and manufacture of broadheads. This manufacturing technology allows a broadhead designer to make fine details and features as integral parts of the broadhead component. Furthermore, this technology enables design features such as a tapered blade to be utilized.